Bonaire set to become Caribbean's
first island with 100% renewable energy

Mar 4, 2008 - renewableenergyworld.com

Late in November 2007 the Dutch-German consortium
EcoPower Bonaire BV announced the signing of a contract
with the Water and Energy Company of Bonaire to build
and operate a sophisticated new sustainable wind-diesel
power plant. From the end of 2009 the power plant
is to supply the small Caribbean island with 10 MW
wind capacity supplemented by 13 MW (bio)diesel power.
Eize de Vries talked with Dirk Berkhout, a board member
of EcoPower partner Econcern, about the project and
its potential as a model for other island or remote
regions.

Along with its 'ABC island' neighbours Aruba and
Curacao, the tiny Caribbean island of Bonaire is located
some 80 km north of the Venezuelan coast. During its
long history it has served as a plantation island
and a salt producer.Today the island also attracts
a modest number of tourists - mainly divers drawn
to its outstanding marine environment - and strives
towards environmental protection and conservation.
With a population of 12,000 persons Bonaire's peak
electricity demand is approximately 12 MW, currently
served by a set of rented container (light-fuel) diesel
gensets with a rated capacity of 12 MW.

TWO PROJECT STAGES

The EcoPower BV consortium comprises the Dutch sustainable
energy group Econcern, the German wind turbine and
system supplier Enercon, and truck and engine manufacturer
MAN of Germany that supplies the diesel generators.The
EcoPower partners aim at transforming today's largely
fossil fuel-based energy supply infrastructure at
the island into one based on the application of 100%
sustainable energy sources within five years. The
project comprises two distinct implementation stages
spread over 2007 and 2009.

In 2007, as part of phase one, EcoPower installed
a 330 kW Enercon E-33 wind turbine at Sorobon on the
southeast coast of Bonaire. This new installation
replaces an obsolete former NedWind turbine that had
not been operational since 1996. The Sorbon site is
characterized by a favourable wind climate, very stable
wind conditions and an average wind speed of about
9.1 m/s.The existing grid cable connection has sufficient
capacity to accommodate one medium-size wind turbine.The
installation activities for the E-33 commenced early
in 2007 and the turbine was commissioned in the May
of that year. Berkhout explained: 'The main objective
of this first project phase is to gain experience
with wind power on Bonaire and to reduce short-term
electricity generation costs.And besides supplying
clean electricity to the island, local staff will
be trained into mastering skills for the long-time
upkeep of Enercon type, direct drive (gearless) turbines.'

The second phase, to be completed during the second
quarter of 2009, involves the construction of a wind-diesel
plant comprising a 10 MW wind farm and a 13 MW diesel
power plant.The diesel plant will be built by truck
and engine manufacturing giant MAN of Germany near
a so-called BOPEC site located at the north-west corner
of the island. The wind farm will comprise either
11 x 900 kW E-44 (rotor diameter 44 metres) or 12
x 800 kW E-48 (rotor diameter 48 metres) turbines.
The E-44 is a new, strong-wind version of the E-48,
with about 1300 operational units in at the end of
2007. Each wind turbine is expected to operate at
a high capacity factor, with some 3000-3500 full load
hours annually. Berkhout said:'We deliberately concentrated
on turbines of sub-megawatt size for transport logistics
and maintenance reasons. All installation and maintenance
activities can, for instance, be performed with a
500-tonne crane. The final decision on the wind farm
design with either the E-44 or E-48 turbines still
has to be taken.The judgement will be based on a thorough
analysis of wind data registered by a measuring mast
we installed this January on site.The wind farm itself
is located on the northeast coast of Bonaire, the
windward side of the island. Under ideal circumstances,
this wind farm alone can fully meet Bonaire's current
electrical needs. Once completed this wind-diesel
combination will be by far the biggest wind- diesel
plant in the world, and already at this early stage
we experience a huge interest of many countries and
island communities from all over the world.'

LOAD BALANCING

EcoPower partner Enercon is in charge of the wind-diesel
load balancing management system. The company already
commercially markets a sophisticated wind powered
water desalination system and a wind-diesel system.
Besides a wind turbine and diesel generator, the latter
comprises an in-house developed flywheel system, a
containerized energy storage battery pack, and a so-called
'black-start' unit. This device is necessary to create
operational grid conditions in an island- type grid
system during start-up.According to Enercon sources,
a wind penetration rate of 90% is achievable with
this system. A demonstration system comprising a 600
kW E-40 turbine and an additional hydrogen production
and storage unit delivered by Hydro, formerly Norsk
Hydro, of Norway, was installed and commissioned on
the Norwegian island Utsira in 2004. A second test
and demonstration wind-diesel system comprising a
330 kW turbine operates in the vicinity of Enercon's
company HQ in Aurich, Germany. A third and larger
wind-diesel was installed on one of the Falkland/Malvinas
islands during the second quarter of 2007 and initial
test results are now available.

Berkhout says that the Bonaire wind-diesel system
is, with a combined capacity of 10 MW wind and 13
MW diesel capacity, on a totally different scale:
'The technology Enercon has developed is at the moment
not fully geared towards the capacities that will
be installed on Bonaire. Our wind-diesel project therefore
initially does not include flywheel technology. We
will install a 2.5 MW battery system to optimize the
wind contribution and to improve the grid quality.
The initial project aim is a wind penetration rate
of 40%-45%, but at a later stage we shall reconsider
the application of additional 'booster' technologies
such as flywheels and other short-term energy storage
systems.' But, he adds, 'with a 40% wind penetration
level and considering the massive scale of the wind-diesel
system, we cannot rule out that some load balancing
and other control difficulties may occur that have
to be solved.' Berkhout points out that reliability
is a key criterion, as there are no alternative supply
systems, such as a cable to the Venezuelan mainland,
in the event of failure.'

Besides an option to boost the wind penetration rate
in future, a second promising track towards achieving
a 100% sustainable electricity supply involves the
extraction of biodiesel fuel from algae.The diesel
power plant will therefore be equipped to burn both
mineral and biofuels. Bonaire has a number of large
saltpans suitable for growing saltwater algae, Berkhout
explains: 'Biodiesel production derived from algae
offers the highest yields per unit of mass of all
plants. At the moment we are conducting a feasibility
study into the entire biodiesel from algae process
chain, an analysis that includes overall economics
for several options.'

EXPENSIVE

Both diesel fuel and its transportation is expensive
and this results at the moment in high electricity
costs for the island's consumer population. Says Berkhout:
'The cost of Bonaire's new wind-diesel system is approximately
US$55 million. We expect that part of this investment
can be recovered by means of CO2 credits. Once the
wind-diesel system is fully operational in 2009 electricity
generation costs will go down. Power consumers on
Bonaire will be among the main beneficiaries.They
can potentially look forward to a 10%-20% reduction
on their electricity bills. Secondly the island's
dependence on highly fluctuating - and as currently
rising - oil prices will be substantially reduced.
The combination of bioenergy production, the wind
turbines and diesel plant will finally give a major
local employment boost to the island's population.
And by 2012 it is conceivable that Bonaire will get
all of its electrical energy from natural, clean renewable
sources.'